A method of stimulating a MicroElectroMechanical Systems (MEMS) structure (e.g. a cantilever), and an optical sensor for use in such a method, using optical radiation pressure instead of electrostatic pressure, or the like. An optical pulse creates optical radiation pressure which stimulates movement of the MEMS structure and then movement of the MEMS structure may be measures. An interrogating light may be input after the optical pulse to measure movement of the MEMS structure. Advantageously, the same light source can be utilized to stimulate movement of the MEMS structure and to measure movement of the MEMS structure.